GENETIC LOADS AND COADAPTIVITY OF CHROMOSOMAL INVERSIONS I - INVERSION POLYMORPHISM AND GENETIC LOAD ON CHROMOSOME O IN A DROSOPHILA-SUBOBSCURA POPULATION FROM PETNICA

Inversion polymorphism on chromosome O and polymorphism for the viabil ity of determining genes have been studied in a natural population of Drosophila subobscura from Petnica (Serbia). The range of inversion po lymorphism and the abundance of particular gene arrangements in the st udy population agree with a general pattern of inversion polymorphism of D. subobscura in Europe. The data obtained on the amount of genetic loads show that the D, subobscura population from Petnica displays a moderate degree of that polymorphism, compared to the other studied po pulations of these species. Therefore, the D. subobscura population fr om Petnica could be tentatively classified as an ecologically central population. Examination association of chromosomal, thus, inversion po lymorphism with gene polymorphism, in the form of genetic loads show t hat differences exist in the mean viability among certain gene arrange ments. The distribution of deleterious genes among chromosome O gene a rrangements were non-random.